The present invention relates to a direction detecting device used to detect a direction of other space vehicle from a space vehicle such as a satellite launched into space.
In the field of the space development, an optical communication system using a space propagation is structured in the satellite launched into space is considered and developed in recent years. Such an optical communication system of a space propagation system is characterized in that optical communication can be performed with simple facilities as compared with the optical communication system of an optical fiber system using an optical fiber as a transmission line.
In this kind of the optical communication system of the space propagation system, unlike the optical fiber system, by use of the space propagation, a base station transmits communication light a communication counterpart station and receives communication light from the communication counterpart station, thereby the optical communication is performed. As a result, it is required that a special structure such as a tracking function of the communication counterpart station (satellite of communication counterpart) be provided.
Specifically, there is a direction detecting device for detecting the direction (azimuth, angle of elevation) of the communication counterpart station to correctly send communication light to the communication counterpart.
Such a direction detecting device must correctly and surely detect the direction of the space vehicle to contribute to the optical communication having high reliability and high accuracy.